Remember to not to forget clearing your journal

Cleanup

Check current disk usage:

sudo journalctl --disk-usage

Use rotate function:

sudo journalctl --rotate

Or

Remove all logs and keep the last 2 days:

sudo journalctl --vacuum-time=2days

Or

Remove all logs and only keep the last 100MB:

sudo journalctl --vacuum-size=100M

How to read logs:

Follow specific log for a service:

sudo journalctl -fu SERVICE

Show extended log info and print the last lines of a service:

sudo journalctl -xeu SERVICE

I mean yeah -fu stands for "follow unit" but its also a nice coincidence when it comes to debugging that particular service.
- 😂😂
--vacuum-time=2days
this implies i keep an operating system installed for that long
- something something nix?
sudo journalctl --disk-usage

panda@Panda:~$ sudo journalctl --disk-usage No journal files were found. Archived and active journals take up 0B in the file system.
hmmmmmm........
user@u9310x-Slack:~$ sudo journalctl --disk-usage Password: sudo: journalctl: command not found
- seems like someone doesn't like systemd :)
Badass! Thanks!
Thank you for this, wise sage.
Your wisdom will be passed down the family line for generations about managing machine logs.
- Glad to help your family, share this wisdom with friends too ☝🏻😃
- Yeah, if I had dependents they'd gather round the campfire chanting these mystical runes in the husk of our fallen society
@RemindMe@programming.dev 6 months
- @ategon@programming.dev is the remindme bot offline?
Actually something I never dug into. But does logrotate no longer work? I have a bunch of disk space these days so I would not notice large log files
- If logrotate doesn't work, than use this as a cronjob via sudo crontab -e Put this line at the end of the file:
  0 0 * * * journalctl --vacuum-size=1G >/dev/null 2>&1
  Everyday the logs will be trimmed to 1GB. Usually the logs are trimmed automatically at 4GB, but sometimes this does not work
If you use OpenRC you can just delete a couple files
Why isn't it configured like that by default?
- It is. The defaults are a little bit more lenient, but it shouldn't gobble up 80 GB of storage.
- Good question, it may depend on the distro afaik

cough80 GiBcough

11.6 mega bites
- Ah, yes, the standard burger size.

Try 60GB of system logs after 15 minutes of use. My old laptop's wifi card worked just fine, but spammed the error log with some corrected error. Adding pci=noaer to grub config fixed it.

I had an issue on my PC (assuming faulty graphics driver or bug after waking from sleep) that caused my syslog file to reach 500GiB. Yes, 500GiB.

You just need a bigger drive. Don't delete anything

Oh lord watch me hoard

Fucking blows my mind that journald broke what is essentially the default behavior of every distro's use of logrotate and no one bats an eye.

I'm not sure if you're joking or not, but the behavior of journald is fairly dynamic and can be configured to an obnoxious degree, including compression and sealing.
By default, the size limit is 4GB:
SystemMaxUse= and RuntimeMaxUse= control how much disk space the journal may use up at most. SystemKeepFree= and RuntimeKeepFree= control how much disk space systemd-journald shall leave free for other uses. systemd-journald will respect both limits and use the smaller of the two values.
The first pair defaults to 10% and the second to 15% of the size of the respective file system, but each value is capped to 4G.
- If anything I tend to have the opposite problem: whoops I forgot to set up logrotate for this log file I set up 6 months ago and now my disk is completely full. Never happens for stuff that goes to journald.
- It can be, but the defaults are freaking stupid and often do not work.

Once I had a mission critical service crash because the disk got full, turns out there was a typo on the logrotate config and as a result the logs were not being cleaned up at all.

edit: I should add that I used the commands shared in this post to free up space and bring the service back up

This once happened to me on my pi-hole. It's an old netbook with 250 GB HDD. Pi-hole stopped working and I checked the netbook. There was a 242 GB log file. :)

Systems/Journald keeps 4GB of logs stored by default.

Title gore

Recently had the jellyfin log directory take up 200GB, checked the forums and saw someone with the same problem but 1TB instead.

2024-03-28 16:37:12:017 - Everythings fine
2024-03-28 16:37:12:016 - Everythings fine
2024-03-28 16:37:12:015 - Everythings fine

logrotate is a thing.

I couldn't tell for a solid minute if the title was telling me to clear the journal or not

I recently discovered the company I work for, has an S3 bucket with network flow logs of several TB. It contains all network activity if the past 8 years.

Not because we needed it. No, the lifecycle policy wasn't configured correctly.